Choker grapple

ABSTRACT

This disclosure pertains to that class of grapples shown as twoline grapples, wherein one line opens and one line closes the grapple. Two embodiments of the invention are disclosed in detail, the first for grapple-loading and the second for grappleyarding, both of which applications are found in the logging industry. In both embodiments a pair of jaws are interconnected at their upper ends by means of a pivot pin for scissors-like relative motion. The closing line is entrained about the pivot pin, thence entrained about a pin mounted substantially at the geometric mid point of one jaw, and thence connected to the other jaw at substantially the same geometric location. Hence, supporting the weight of the jaws by the closing line causes the jaws to close about a log or object therebetween; in so closing the jaws, that part of the closing line which spans the jaw opening moves downward, thus choking off the opening and coming to rest upon and tending to bite into the log(s) or object between the jaws. The opening line is interconnected to a pair of either rigid or flexible opening members, one each of which is connected to a point midway between the upper and lower ends of each jaw. Hence, supporting the jaws by the opening line causes the jaws to fall open under the influence of gravity, much as in the case of a clamshell bucket. In the first embodiment of the invention, the opening members are rigid and pivotally interconnected at their upper ends and pivotally connected at their lower ends each to one jaw. In the second embodiment of the invention, the opening members are flexible and connected directly to the underside of a grapple-yarding carriage, the &#39;&#39;&#39;&#39;opening line&#39;&#39;&#39;&#39; in effect being the cable system supporting the carriage; the flexibility of the opening members allows the grapple-jaws to swivel with respect to the carriage.

United States Patent Johnson [54] CHOKER GRAPPLE [72] Inventor: Norman A. Johnson, 5325 10th Ave., Delta 742 British Columbia, Canada [22] Filed: June 8, 1970 [21] Appl. No.: 44,474

[52] [1.8. CI ..294/l11, 294/112 Priniary Examiner-Evon C. Blunk Assistant Examiner-l. Kenneth Silverman [57] ABSTRACT This disclosure pertains to that class of grapples shown as two-line grapples, wherein one line opens and one line closes the grapple. Two embodiments of the invention are disclosed in detail, the first for grappleloading and the second for grapple-yarding, both of which applications are found in the logging industry. In both embodiments a pair of jaws are interconnected [451 Sept. 12, 1972 at their upper ends by means of a pivot pin for scissors-like relative motion. The closing line is entrained about the pivot pin, thence entrained about a pin mounted substantially at the geometric mid point of one jaw, and thence connected to the other jaw at substantially the same geometric location. Hence, supporting the weight of the jaws by the closing line causes the jaws to close about a log or object therebetween; in so closing the jaws, that part of the closing line which spans the jaw opening moves downward, thus choking off the opening and coming to rest upon and tending to bite :into the log(s) or object between the jaws. The opening line is interconnected to a pair of either rigid or flexible opening members, one each of which is connected to a point' midway between the upper and lower ends of each jaw. Hence, supporting the jaws by the opening line causes the jaws to fall open under the influence of gravity, much as in the case of a clamshell bucket. In the first embodiment of the invention, the opening members are rigid and pivotally interconnected at their upper ends and pivotally connected at their lower ends each to one jaw. In the second embodiment of the invention, the opening members are flexible and connected directly to the underside of a grapple-yarding carriage, the opening line in effect being the cable system supporting the carriage; the flexibility of the opening members allows the grapplejaws to swivel with respect to the carriage.

3 Claims, 10 Drawing Figures Patented Sept. 12, 1972 4 Sheets-Sheet 1 Patented Sept. 12, 1972 4 Sheets-Sheet 2 Patented Sept. 12, 1972 4 Sheets-Sheet 5 Patented Sept. 12, 1972 4 Sheets-Sheet 4 CHOKER GRAPPLE This invention relates to novel improvements in devices which are known in the art to which they pertain as grapples, or to devices such as clamshell buckets and tongs that belong to or are of the general character of grapples. In their simplest form, grapples and tongs are substantially symmetrical four-bar mechanisms whose operation is effected by supporting lines which employ gravity to open and close the grapple jaws.

In the logging industry, grapples have found wide usage in the loading and yarding of logs. Principle requirements for logging grapples are compactness, lightness, simplicity of construction, adequacy of closing force, dependability of opening mechanism, and effective leading of the closing and opening cables into the grapple mechanism.

A further important requirement is holding dependability; that is to say, while the grapple closing force may be adequate to prevent logs from vertically falling out of the grapple jaws, the holding characteristics of the jaws may not be such as to prevent the logs slipping out longitudinally. This is particularly critical in grappleyarding where production is directly related to the number of logs yarded in per turn and where it is therefore desirable to be able to hold effectively more than one log in the grapple. Holding dependability in conventional grapples depends heavily upon large spikes or teeth on the inner surfaces of the jaws. However, such spikes and teeth have been known to cause undesirable log damage and, in any case, do not provide the holding effectiveness of conventional choker cables which bite into a log to an extent which is in direct proportion to the weight of the log. The present invention is directed toward combining the operating versatility of log grapples with the holding dependability of log chokers.

Still other important requirements or desirable fea tures particular to grapple-yarding are a grapple assembly which is short, both with thegrapple jaws open and closed, and a facility for the grapple to maintain a preferred orientation with respect to the yarding road while still being free to swivel with respect to the yard ing carriage. The shortness requirement of the grapple assembly is dictated by the scant deflection available in many yarding settings, particularly near the tailblock end or outskirts of the setting. The preferred orientation requirement is related to the desirability of felling trees across a yarding road to permit the greatest road width possible for each tailblock position; i. e., if the trees are felled across the yarding road, the preferred orientation of the jaws is parallel to the road. The swiveling requirement arises from the necessity of the grapple to adjust universally to gravitational forces on a turn of logs as well as those forces imparted to the grapple during yarding when the turn or grapple contacts the ground, standing trees, stumps, boulders, or other felled trees.

It is one object of this invention to provide an improved grapple assembly, especially designed for log loading and yarding, of compact and light construction, whose overall height when fully open is substantially the same as its overall height when fully closed, and wherein the closing line of the grapple spans the opening of the grapple jaws and bears upon and bites into a log or logs between the jaws.

It is a further object of this invention to provide a jaw closing force substantially equal to or greater than the force required to resist the force of gravity on the grappled load, irrespective of the size of the load or the position of the grapple jaws relative to one another.

Yet another object of this invention is to provide a grapple closing mechanism such that the members to which an opening line is connected may be either rigid or flexible, of simple construction, and wherein the closing force between the jaws does not depend upon compressive forces in those opening members.

Still another object of the invention is to provide a grapple closing mechanism which applies a closing force to the jaws below the jaw pivot pin and directly across the jaw opening.

It is still another object of this invention to provide an embodiment wherein the opening members are flexible and may be connected in a preferred orientation directly to the underside of a grapple-yarding carriage, the flexibility of those members permitting the grapple jaws to swivel and move universally with respect to the grapple carriage.

Still further object and advantages of the present invention reside in the details of construction of the two embodiments of the invention disclosed herein.

These and further objects of the invention will be evident from a study of the following disclosure and the accompanying drawings which illustrate improved details of construction of two preferred embodiments of the invention, the first for grapple-loading logs and the second for grapple-yarding logs. These embodiments are merely exemplary and are not intended to detract from the full scope of the invention as set out in the annexed claims.

In the drawings, wherein like numerals refer to like parts:

FIG. 1 is a front view showing a loading grapple assembly in accordance with the present invention with the jaws of the grapple shown in their fully open position;

FIG. 2 is a plan view of the arrangement shown in FIG. 1;

FIG. 3 is a partial horizontal transverse section substantially in the plain indicated by line 3-3;

FIG. 4 is a front view showing a grapple assembly as in FIG. 1 but wherein the jaws are in their fully closed position;

FIG. 5 is a front view showing a grapple assembly as in FIG. 1 but wherein the jaws are partially closed about a log therebetween, the closing cable bearing down upon and biting into the top of the log;

FIG. 6 is a front view of a yarding grapple and grapple-carriage in accordance with the present invention with the jaws of the grapple in their fully open position;

FIG. 7 is a partial view of the grapple yarding carriage taken along line 7 --7 in FIG. 6;

FIG. 8 is a vertical transverse section of the grapple pivot pin, jaws, and swivel guide taken along 88 in FIG. 6;

FIG. 9 is a front view of the arrangement in FIG. 6 but wherein the jaws are shown in their fully closed position;

FIG. 10 is a front view of the arrangement in FIG. 6 but wherein the jaws are shown partially closed about a turn of three logs, the closing line bearing down upon and biting intothetopmostlog.

Turning now to the drawings, the first embodiment of the present invention is shown in FIGS. 1, 2, 3, 4, and 5. FIG. 1 shows the grapple assembly with jaws and 21 in the fully open position; FIG. 2 shows a plan view of FIG. 1. Opening members 22 and 23 support and maintain the jaws in the open position, their being pivotally connected at their lower ends respectively to jaws 20 and 21 by pivot pins 24 and 25 and at their upper ends pivotally interconnected by an upper pivot means, namely pivot pin 26. Rotatably mounted on pivot pin 26 is swivel-head 27 to which is secured a lifting means, namely holding eye 28, and cable guide means 29. A holding line or chain may be operatively connected to holding eye 28, thereby supporting jaws 20 and 21 in the open position by means of opening members 22 and 23. Closing flexible tension means, namely cable 30, passes through cable guide means 29, is entrained about a jaw pivot means, namely pin 31, by means of sheave means 32 and about a jaw pin means, namely pin 33, by means of sheave means 34, and terminates at a connecting means, namely wedge which is an integral structural part of jaw 21.

It is apparent from the foregoing that opening members 22 and 23 may be flexible tension members. Moreover, closing cable 30 may terminate on jaw 21 by means of an eye at the end of the closing line and a pin or clevis mounted on jaw 21; alternatively, closing line 30 could terminate on jaw 21 by means of a fixed eye situate on jaw 21 and a ferrule on the end of cable 30: in any case allowance should be made for the change in direction of cable 30 relative to jaw 21 as jaws 20 and 21 open and close. It is equally as apparent that holding eye 28 could be affixed to either of opening members 22 and 23 and that cable guide means 29 could be swivel-mounted on or otherwise secured to either or both of opening members 22 and 23. It should also be apparent that either or both of opening members 22 and 23 could be L-shaped to form a horizontal head area at the top of the grapple assembly or, alternatively, opening members 22 and 23 could be pivotally connected to a horizontal cross-head, holding eye 28 and cable guide means 29 being secured to the horizontal area thus formed.

In the position of the grapple assembly as shown in FIG. 1, the weight of the grapple being supported by holding eye 28, closing cable 30 would be substantially slack. Turning to FIG. 3 (a sectional view taken in FIG. 1 along line 3-3) in conjunction with FIGS. 1, 2, and 4, entrainment of the slack closing line 30 about pivot pin 31 and sheave 31 and sheave 32 is maintained by guide stubs 36 and 37 and about pin 33 and sheave 34 by means of housing 38, an integral structural part of jaw 20.

To prevent jaws 20 and 21 from falling further open than the position shown in FIG. 1, opening stop means 39 and 40 are secured respectively to jaws 20 and 21, interacting against each other as shown in FIGS. 1 and 3. To prevent jaws 20 and 21 from closing to a greater extent than desired when the weight of the grapple assembly is supported by closing cable 30 as shown in FIG. 4, closing stop means 41 and 42 come to rest respectively against jaws 21 and 20. Pads 43, and 44 are adapted to neutralize the twisting effect of the forces of contact between jaws 20 and 21 with a log as it is grappled; these pads are integral structural parts respectively of jaw 20, stop means 41, housing 38 and of jaw 2], stop means 42, and wedge 35.

Insofar as structural considerations beyond those already mentioned concerning jaws 20 and 21 are concerned, with reference to FIGS. 1, 2, and 3, opening members 22 and 23 are comprised of sideplates 45 and 46 and web 47. Jaws 20 and 21 have hubs 48 and 49, in which pins 24 and 25 are mounted, these hubs being integral structural parts of the jaws so as to distribute the opening forces of opening members 22 and 23 into the jaws. The location of the center of gravity of the jaws 20 and 21 determines the speed with which the jaws will open when the weight of the grapple assembly is shifted from closing cable 30 to holding eye 28. The location of the jaw centers of gravity is improved by counterweight extensions 110 and 111 at the upper ends of jaws 20 and 21.

FIG. 5 shows the grapple assembly of the first embodiment of the invention grappling log 50. FIG. 5 illustrates the manner by which closing cable 30, while drawing the jaws 20 and 21 tightly closed around log 50, bites into an uppermost arcuate portion 51 of log 50 thereby securing the log against not only longitudinally slipping out of the jaws in direction 52 but also from levering upwards at its forward most end 53 in such manner as to spread jaws 20 and 21, thereby allowing log 50 to fall vertically out of the jaws.

Let us turn now to the second embodiment of the present invention as depicted in FIGS. 6, 7, 8, 9, and 10. FIG. 6 shows the grapple jaws in the fully open position. The grapple assembly in this case comprises jaws and 61, opening chains 62 and 63 and grapple yarding carriage 64. The opening chains 62 and 63 are connected to jaws 60 and 61 respectively by means of holding eyes and 66, both of which eyes are respectively integral structural parts of jaws 60 and 61. At their upper ends, opening chains 62 and 63 are respectively secured to carriage 64 by means of pins 67 and 68 and shackles 69 and 70.

The grapple yarding carriage 64 is supported in this case by a cable system comprised of haulback line 71 and mainlines 72 and 73. Haulback line 71 passes out of FIG. 6 to the right, about a tailblock not shown and is ultimately secured to carriage. 64 by means of swivel shackle 74 and pin 95.

With reference to FIGS. 6 and 7, mainline 73 is entrained about pin 91 by means of sheave 75 in carriage 64, passes through butt-plate 82, and terminates in swivel shackle 76; mainline 72 terminates in swivel shackle 77. Both mainlines are connected by pins 78 and 79 respectively to a three-hole tag-plate 80. Connected to the third hole of tag-plate 80 is a third or closing line swivel-shackle, not seen in FIG. 6 but directly behind swivel shackle 76, to which is secured grapple closing line 81. Closing cable 81 passes through buttplate 82, is entrained about pin 91 by means sheave 83, passes through cable-guide 84, through swivel guide means 85, is entrained about a jaw pivot means, namely pin 86, by means of sheave 87, is entrained about a jaw pin means, namely pin 88, by means of sheave 89, and terminates in wedge 90, the latter an integral structural part of jaw 61. Swivel guide means 85 and sheave 87 are rotatably mounted on pivot pin 86; sheave 89 is rotatably mounted on pin 88. Besides being supported by mainlines 72 and 73 and haulback 71 at pin 95, carriage 64 is further supported in the yarding cable system by means of snatch block 92, shackle 93 and pin 94.

It should be apparent from the foregoing description of the yarding cable system and rigging that a paying out of the haulback line 71 and winding in of mainlines 72 and 73 at a yarding machine located to the left of FIG. 6 will cause the grapple assembly to move from right to left in FIG. 6, Le, in direction 112. Conversely, a paying out of mainlines 72 and 73 and winding in of haulback line 71 will cause the grapple assembly to move from left to right, i. e., in direction 113. Holding haulback line 71, paying out mainline 73 and winding in mainline 72 will cause tag-plate 80 and the shackle assembly thereto attached to movein direction 112, thereby drawing closing cable 81 up through cable guide 84 and causing the grapple jaws 60 and 61 eventually to assume the position shown in FIG. 9. The grapple may be again opened by paying out mainline 72 and winding in mainline 73.

The jaws 60 and 61 are prevented from falling more fully open than their relative position shown in FIG. 6 by opening stop means as comprised of shackle 76 and the aforementioned closing line shackle immediately behind shackle 76 coming to rest against butt-plate 82, the butt-plate 82 resting ultimately against the forward portions of center plate 96 and side plates 97 and 98 of carriage 64 (FIG. 7). However, it should be apparent that the same stopping effect could be achieved by letting the under surface of upper plate 114 of swivel cable-guide 85 serve as a closing stop means by coming to rest upon the upper surfaces of jaws 60 and 61 as shown in FIGS. 6 and 8. j

The jaws 60 and 61 of the grapple-carriage assembly, as shown in FIG. 9, are limited in the extent to which they may close and overlap by closing stop means 99 and 100 mounted on the adjacent surfaces of jaws 60 and 61 and forming an integral structural portion thereof. It will be noted that a differential force between mainlines 72 and 73 (see FIG. 6) in favor of mainline 72 of magnitude equal to or greater than the weight of the grapple jaws and grappled load will cause the grapple jaw assembly to rise until swivel cableguide 85 assumes a position 101 in direct contact with cable guide 84, as shown in FIG. 9. The raising of the grapple-jaw assembly thus draws slack in opening chains 62 and 63 and permits the jaws to swivel about the axis of the closing line with respect to the grapple carriage 64. This effect is seen in FIG. 10.

For the best stability of the grapple jaw assembly 102 as opening occurs from the position shown in FIG. 9, the center of gravity of the assembly should be below the level of holding eyes 65 and 66.

Entrainment of the mainline 73 and the closing cable 81 about sheaves 75 and 83 in carriage 64 is achieved by arcuate members 103 and 104 joining side plates 97 and 98 to center plate 96 in FIG. 7. These arcuate surfaces also facilitate reeving the cable in the first instance. Swivel guide 85 as shown in FIGS. 6, 8, 9, and 10, swivels about jaw pivot pin 86 and maintains entrainment of closing cable 81 about sheave 87. Sheave housing 105 is an integral structural part of jaw 60 andmaintains entrainment of a slack closing cable 81 about sheave 89.

FIG 10 shows the grapple jaws of the second embodiment of the present invention in a partially closed position about a turn of three logs 106, 107, and 108. It is apparent that closing cable 81 is bearing down upon and biting into upper log 106 thereby wedging it downward between logs 107 and 108 and forcing logs 107 and 108 outward against the grapple jaws and 61. Hence all three logs are held fast and prevented from slipping out of the grapple in direction 109 and the balance of forces between closing cable 81 and jaws 60 and 61 is such that the logs cannot jointly or individually lever upward at their forward end and thereby fall out of the grapple jaws. In FIG. 10, swivel cable-guide has been drawn up tight against cableguide 84 and the loaded grapple assembly 102 has swiveled approximately about a substantially vertical axis with respect to the carriage 64.

It will be appreciated that the foregoing discloses only two preferred embodiments of the invention. Further, many modifications, changes, and equivalents will readily occur to those skilled in the present art, particularly in view of the above teachings. Therefore the present invention is not to be construed as limited to the specific details illustrated and described above.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A scissors-type grapple assembly comprising a pair of jaws each having upper and lower end-portions, jaw pivot means pivotally interconnecting said upper-endportions of said jaws, a pair of opening members, each one (end of each) of said pair of opening members operatively connected at one end to one jaw (each) of said pair of jaws respectively intermediate said upper and lower end-portions, the other ends of said opening members operatively connected to a lifting means, jaw pin means secured to one of said jaws intermediate said upper and lower end-portions, connecting means secured to the other of said jaws intermediate said upper and lower end-portions, swivel guide means pivotally mounted on said jaw pivot means to swing freely with respect to said pair of jaws, closing flexible tension means passing through said. swivel guide means and entrained about said jaw pivot means and further entrained about said jaw pin means and thence operatively secured to said connecting means (closing stop means and opening stop means adapted to limit relative angular motion of said jaws with respect to said jaw pivot means).

2. A scissors type grapple assembly as defined in Claim 1, said lifting means comprising a grapple-yarding carriage and yarding cable system, said yarding cable system having a mainline and a haulback line, said other ends of said opening members operatively connected to (a) said grapple-yarding carriage (said lifting means comprising a several part yarding cable system), said closing flexible tension means (operatively secured to at least one part of said yarding cable system) interconnected to said mainline.

3. A scissors-type grapple assembly comprising a pair of jaws having upper and lower end portions, jaw pivot means pivotally interconnecting said upper end portions of said jaws, a pair of flexible opening members each at one end operatively connected to one of said jaws intermediate said upperand lower end portions,

jaw pivot means, a closing cable secured at one end to at least one part of a several part yarding cable system, said closing cable passing through said swivel guide means and entrained about said first and second sheave means and ultimately secured to said connecting means, closing and opening stop means adapted to limit relative angular motion of said jaws with respect to said jaw pivot means.

UNITED STATES PATENT OFFICE CERTIFICATE OF CDRRECTION PatentNo, 3,690,716 Dated September 12, 1972 Inventor-(s) NORMAN A. JOHNSON I I t is certified that error appears in the above-identified patent and that said Letters Patent are hereb corrected as shown below:

In columns 6, 7 and 8, cancel claims 1 through 3 and j substitute the following: I v f w j r 1. A scissors-type grapple assembly comprising a pair 50f jaws each having upper and lower end-portions, jaw pivot means pivotally interconnecting said upper end-portions of 1 said jaws a pair of opening members each one of said pair of opening members operatively connected at one end to one jaw of said pair of jaws respectively intermediate said upper andlower end-portions, the other ends of said opening members operatively connected to a lifting means, jaw pin means secured to one of said jaws intermediate said upper and lower end-portions, connecting means secured to the other of said jaws intermediate said upper andQlower end- I portions;"swive1 guide means pivotally mounted onsaid jaw pivot means to swing freely with respect to said pair of jaws, closing flexible tension means passing through said swivel guide means and entrained about said jaw pivot means and further entrained about said jaw pin means and thence Y op erati'vely secured'fto said connecting means. g

j l 2. A scissors type grapple assembly as defined in Claim 1, said lifting means comprising a grapple-yarding carriage and yarding cable system, said yarding'cable system having a mainline and a haulback line, said other ends of said opening member's operatively connected to said grappleiyardingcarriage, said. closing flexible tension means interconnected to said mainline.

. 3., A scissors type grapple assembly comprising a pair 0f jaws each having upper and lower endportions, jaw pivot FORM POI-105C (10-59) PATENT NO. 3,690, 716 PAGE 2 means p-ivota'lly interconnecting said upper end-portions of said jaws, a pair of flexible opening members each at one end operatively connected to one of said jaws.

intermediate said upper and lower end-portions, the other ends of each of said flexible opening members operatively connected to a grapple-yarding carriage, a jaw pin means secured to one of said jaws intermediate said upper and lower end-portions, connecting means secured to the other of said jaws intermediate said upper and lower end-portions, a first sheave means rotatably mounted on said jaw pivot means, a second sheavemeans rotatably mounted on said jaw pin means swivel guide means pivotally mounted on said jaw pivot means a closing cable passing through said swivel guide means and entrained about said first and second sheave means and ultimately secured to said connecting means.

Signedland sealed this 13th day of August 1974.

(SEAL) Attest:

McCOY M. GIBSON, JR. (3. MARSHALL DANN Attesting Officer Commissioner of Patents 

1. A scissors-type grapple assembly comprising a pair of jaws each having upper and lower end-portions, jaw pivot means pivotally interconnecting said upper end-portions of said jaws, a pair of opening members, each one (end of each) of said pair of opening members operatively connected at one end to one jaw (each) of said pair of jaws respectively intermediate said upper and lower end-portions, the other ends of said opening members operatively connected to a lifting means, jaw pin means secured to one of said jaws intermediate said upper and lower endportions, connecting means secured to the other of said jaws intermediate said upper and lower end-portions, swivel guide means pivotally mounted on said jaw pivot means to swing freely with respect to said pair of jaws, closing flexible tension means passing through said swivel guide means and entrained about said jaw pivot means and further entrained about said jaw pin means and thence operatively secured to said connecting means (closing stop means and opening stop means adapted to limit relative angular motion of said jaws with respect to said jaw pivot means).
 2. A scissors type grapple assembly as defined in Claim 1, said lifting means comprising a grapple-yarding carriage and yarding cable system, said yarding cable system having a mainline and a haulback line, said other ends of said opening members operatively connected to (a) said grapple-yarding carriage (said lifting means comprising a several part yarding cable system), said closing flexible tension means (operatively secured to at least one part of said yarding cable system) interconnected to said mainline.
 3. A scissors-type grapple assembly comprising a pair of jaws having upper and lower end portions, jaw pivot means pivotally interconnecting said upper end portions of said jaws, a pair of flexible opening members each at one end operatively connected to one of said jaws intermediate said upper and lower end portions, the other ends of each of said flexible opening members operatively connected to a grapple-yarding carriage, a jaw pin means secured to one of said jaws intermediate said upper and lower end portions, connecting means secured to the other of said jaws intermediate said upper and lower end portions, a first sheave means rotatably mounted on said jaw pivot means, a second sheave means rotatably mounted on said jaw pin means, swivel guide means rotatably mounted on said jaw pivot means, a closing cable secured at one end to at least one part of a several part yarding cable system, said closing cable passing through said swivel guide means and entrained about said first and second sheave means and ultimately secured to said connecting means, closing and opening stop means adapted to limit relative angular motion of said jaws with respect to said jaw pivot means. 